OK, let's crack this. We're given 21 and our task is to multiply it by 192. Essentially, we'll be adding 21 to itself 192 times.
Step 1: 0 + 21 = 21
Step 2: 21 + 21 = 42
Step 3: 42 + 21 = 63
Step 4: 63 + 21 = 84
Step 5: 84 + 21 = 105
Step 6: 105 + 21 = 126
Step 7: 126 + 21 = 147
Step 8: 147 + 21 = 168
Step 9: 168 + 21 = 189
Step 10: 189 + 21 = 210
Step 11: 210 + 21 = 231
Step 12: 231 + 21 = 252
Step 13: 252 + 21 = 273
Step 14: 273 + 21 = 294
Step 15: 294 + 21 = 315
Step 16: 315 + 21 = 336
Step 17: 336 + 21 = 357
Step 18: 357 + 21 = 378
Step 19: 378 + 21 = 399
Step 20: 399 + 21 = 420
Step 21: 420 + 21 = 441
Step 22: 441 + 21 = 462
Step 23: 462 + 21 = 483
Step 24: 483 + 21 = 504
Step 25: 504 + 21 = 525
Step 26: 525 + 21 = 546
Step 27: 546 + 21 = 567
Step 28: 567 + 21 = 588
Step 29: 588 + 21 = 609
Step 30: 609 + 21 = 630
Step 31: 630 + 21 = 651
Step 32: 651 + 21 = 672
Step 33: 672 + 21 = 693
Step 34: 693 + 21 = 714
Step 35: 714 + 21 = 735
Step 36: 735 + 21 = 756
Step 37: 756 + 21 = 777
Step 38: 777 + 21 = 798
Step 39: 798 + 21 = 819
Step 40: 819 + 21 = 840
Step 41: 840 + 21 = 861
Step 42: 861 + 21 = 882
Step 43: 882 + 21 = 903
Step 44: 903 + 21 = 924
Step 45: 924 + 21 = 945
Step 46: 945 + 21 = 966
Step 47: 966 + 21 = 987
Step 48: 987 + 21 = 1008
Step 49: 1008 + 21 = 1029
Step 50: 1029 + 21 = 1050
Step 51: 1050 + 21 = 1071
Step 52: 1071 + 21 = 1092
Step 53: 1092 + 21 = 1113
Step 54: 1113 + 21 = 1134
Step 55: 1134 + 21 = 1155
Step 56: 1155 + 21 = 1176
Step 57: 1176 + 21 = 1197
Step 58: 1197 + 21 = 1218
Step 59: 1218 + 21 = 1239
Step 60: 1239 + 21 = 1260
Step 61: 1260 + 21 = 1281
Step 62: 1281 + 21 = 1302
Step 63: 1302 + 21 = 1323
Step 64: 1323 + 21 = 1344
Step 65: 1344 + 21 = 1365
Step 66: 1365 + 21 = 1386
Step 67: 1386 + 21 = 1407
Step 68: 1407 + 21 = 1428
Step 69: 1428 + 21 = 1449
Step 70: 1449 + 21 = 1470
Step 71: 1470 + 21 = 1491
Step 72: 1491 + 21 = 1512
Step 73: 1512 + 21 = 1533
Step 74: 1533 + 21 = 1554
Step 75: 1554 + 21 = 1575
Step 76: 1575 + 21 = 1596
Step 77: 1596 + 21 = 1617
Step 78: 1617 + 21 = 1638
Step 79: 1638 + 21 = 1659
Step 80: 1659 + 21 = 1680
Step 81: 1680 + 21 = 1701
Step 82: 1701 + 21 = 1722
Step 83: 1722 + 21 = 1743
Step 84: 1743 + 21 = 1764
Step 85: 1764 + 21 = 1785
Step 86: 1785 + 21 = 1806
Step 87: 1806 + 21 = 1827
Step 88: 1827 + 21 = 1848
Step 89: 1848 + 21 = 1869
Step 90: 1869 + 21 = 1890
Step 91: 1890 + 21 = 1911
Step 92: 1911 + 21 = 1932
Step 93: 1932 + 21 = 1953
Step 94: 1953 + 21 = 1974
Step 95: 1974 + 21 = 1995
Step 96: 1995 + 21 = 2016
Step 97: 2016 + 21 = 2037
Step 98: 2037 + 21 = 2058
Step 99: 2058 + 21 = 2079
Step 100: 2079 + 21 = 2100
Step 101: 2100 + 21 = 2121
Step 102: 2121 + 21 = 2142
Step 103: 2142 + 21 = 2163
Step 104: 2163 + 21 = 2184
Step 105: 2184 + 21 = 2205
Step 106: 2205 + 21 = 2226
Step 107: 2226 + 21 = 2247
Step 108: 2247 + 21 = 2268
Step 109: 2268 + 21 = 2289
Step 110: 2289 + 21 = 2310
Step 111: 2310 + 21 = 2331
Step 112: 2331 + 21 = 2352
Step 113: 2352 + 21 = 2373
Step 114: 2373 + 21 = 2394
Step 115: 2394 + 21 = 2415
Step 116: 2415 + 21 = 2436
Step 117: 2436 + 21 = 2457
Step 118: 2457 + 21 = 2478
Step 119: 2478 + 21 = 2499
Step 120: 2499 + 21 = 2520
Step 121: 2520 + 21 = 2541
Step 122: 2541 + 21 = 2562
Step 123: 2562 + 21 = 2583
Step 124: 2583 + 21 = 2604
Step 125: 2604 + 21 = 2625
Step 126: 2625 + 21 = 2646
Step 127: 2646 + 21 = 2667
Step 128: 2667 + 21 = 2688
Step 129: 2688 + 21 = 2709
Step 130: 2709 + 21 = 2730
Step 131: 2730 + 21 = 2751
Step 132: 2751 + 21 = 2772
Step 133: 2772 + 21 = 2793
Step 134: 2793 + 21 = 2814
Step 135: 2814 + 21 = 2835
Step 136: 2835 + 21 = 2856
Step 137: 2856 + 21 = 2877
Step 138: 2877 + 21 = 2898
Step 139: 2898 + 21 = 2919
Step 140: 2919 + 21 = 2940
Step 141: 2940 + 21 = 2961
Step 142: 2961 + 21 = 2982
Step 143: 2982 + 21 = 3003
Step 144: 3003 + 21 = 3024
Step 145: 3024 + 21 = 3045
Step 146: 3045 + 21 = 3066
Step 147: 3066 + 21 = 3087
Step 148: 3087 + 21 = 3108
Step 149: 3108 + 21 = 3129
Step 150: 3129 + 21 = 3150
Step 151: 3150 + 21 = 3171
Step 152: 3171 + 21 = 3192
Step 153: 3192 + 21 = 3213
Step 154: 3213 + 21 = 3234
Step 155: 3234 + 21 = 3255
Step 156: 3255 + 21 = 3276
Step 157: 3276 + 21 = 3297
Step 158: 3297 + 21 = 3318
Step 159: 3318 + 21 = 3339
Step 160: 3339 + 21 = 3360
Step 161: 3360 + 21 = 3381
Step 162: 3381 + 21 = 3402
Step 163: 3402 + 21 = 3423
Step 164: 3423 + 21 = 3444
Step 165: 3444 + 21 = 3465
Step 166: 3465 + 21 = 3486
Step 167: 3486 + 21 = 3507
Step 168: 3507 + 21 = 3528
Step 169: 3528 + 21 = 3549
Step 170: 3549 + 21 = 3570
Step 171: 3570 + 21 = 3591
Step 172: 3591 + 21 = 3612
Step 173: 3612 + 21 = 3633
Step 174: 3633 + 21 = 3654
Step 175: 3654 + 21 = 3675
Step 176: 3675 + 21 = 3696
Step 177: 3696 + 21 = 3717
Step 178: 3717 + 21 = 3738
Step 179: 3738 + 21 = 3759
Step 180: 3759 + 21 = 3780
Step 181: 3780 + 21 = 3801
Step 182: 3801 + 21 = 3822
Step 183: 3822 + 21 = 3843
Step 184: 3843 + 21 = 3864
Step 185: 3864 + 21 = 3885
Step 186: 3885 + 21 = 3906
Step 187: 3906 + 21 = 3927
Step 188: 3927 + 21 = 3948
Step 189: 3948 + 21 = 3969
Step 190: 3969 + 21 = 3990
Step 191: 3990 + 21 = 4011
Step 192: 4011 + 21 = 4032

So, 21*192 = 4032